Experimental and computational exploration of indolizinyl carbene generation. A route to biindolizines.
Experimental and computational exploration of indolizinyl carbene generation. A route to biindolizines.
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DOI：
10.1021/jo200157q
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
I. Lahoz;C. López;A. Navarro‐Vázquez;M. Cid
中科院分区：
文献类型：
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作者：
I. Lahoz;C. López;A. Navarro‐Vázquez;M. Cid
在以前的工作中，（E）-2-烯炔基吡啶通过碱催化的E/Z异构化，然后通过5-exo-dig假coarctate环化得到中氮茚基单重态卡宾。我们在此报告，在丙烯酸乙酯的存在下，这些卡宾进行立体选择性顺式环丙烷化，主要是由于在过渡态的静电相互作用。该卡宾生成方案的范围已通过制备对称的双（吡啶基）炔在一锅反应中自发地提供的biindolizine核心进一步探讨。这种转换的计算表征表明高度异步双环化。
In previous work, (E)-2-enynyl pyridines were reported to yield indolizinyl singlet carbenes through base-catalyzed E/Z isomerization followed by a 5-exo-dig pseudocoarctate cyclization. We report herein that in the presence of ethyl acrylate these carbenes undergo stereoselective cis-cyclopropanation due mainly to electrostatic interactions in the transition state. The scope of this carbene generation scheme has been further explored through the preparation of a symmetric bis(pyridylenyl)alkyne which spontaneously furnished the biindolizine core in a one-pot reaction. Computational characterization of this transformation suggests a highly asynchronous double cyclization.